Looking around at the rest of the group struggling with their masks, I decide this is probably the best course of action and pull it over my head.

I’m 30ft underground in a top secret Soviet bunker in the heart of Latvia on the 100th anniversary of the country’s first declaration of independence — and seeing what life was like under Soviet occupation.

The corridors in the bunker were painted olive green on the advice of Soviet psychologists

Tourist attraction: Known by its code name, the Pension, the bunker was completed in 1982

The bunker, which has recently been opened to the public, is accessible only through the back door of the Sixties rehabilitation centre above it in Ligatne, 50 miles from Riga in the Gauja National Park.

Known by its code name, the Pension, the bunker was completed in 1982, and served as one of the USSR’s strategic hideouts — so secretive its whereabouts were classified until 2003.

At full capacity, up to 250 workers manned this 90-room network, 2,000 square metre site, in preparation for a full-scale nuclear war. From the monolithic radio equipment down to the Soviet decor on the canteen walls, not much has changed since.

Sealed off from the outside world with a 15ft layer of concrete, our guide Maria tells us that the bunker is equipped with its own power supply, a well for drinking water and enough supplies for three months.

She then leads us off through the maze of olive green corridors, painted so on the advice of Soviet psychologists who believed the colour promoted well-being.

Our first stop is the communications room, where there’s a stack of tape reels used by KGB agents to record phone calls. In the next room, below a Lenin facade, is a desk with a red phone, which Maria informs us was the Kremlin hotline.

Chlling: This room features a map, conference table and figurehead marked ‘Lenins’

In an adjoining room there is a small bed — the only one in the complex — reserved for Boris Pugo, the Minister of Interior Affairs who committed suicide following the collapse of the Soviet Union in 1991.

But the best has been saved to last.

The war room, straight out of Dr Strangelove, is lined with maps and charts detailing strategic points of interest. One in particular catches my eye. It’s a map of the UK with my hometown, Reading, marked in Cyrillic, making me shudder to think I may have been a Soviet target.

Alex ate in the canteen during her visit where she was served watery dumplings with a dollop of sour cream

Above the door is a flashing red light. I enquire what it’s for and Maria replies: ‘Code red — immediate evacuation.’

Taking our cue, we’re directed into the canteen where we get a plate of watery dumplings with a dollop of sour cream.

I look at all the Soviet propaganda. One poster is of a surly lady with her forefinger to her mouth reminding comrades their work must remain top secret. We couldn’t be more suspicious of Russia today and a visit here will do little to reassure you.

The bunker is accessible only through the back door of the Sixties rehabilitation centre above it in Ligatne, 50 miles from Riga in the Gauja National Park (pictured)

TRAVEL FACTS

Tours of Ligatne bunker cost £12, including a meal. For more information visit bunkurs.lv.

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